Flora & Fauna

Red, purple, or dark blue-green slime mats that smother the sandbed and rockwork with a slimy, oxygen-depleting film. Technically a bacterium. Caused by low nitrates, poor flow, and high dissolved organics. A 3-day blackout, hydrogen peroxide spot-treatment, and improved flow usually break the cycle.

Feathery, fern-like dark green algae that is notoriously difficult to eliminate — one of the most persistent reef tank nuisances. Resistant to most herbivores. Best controlled by raising magnesium to 1500–1800 ppm for 2–4 weeks (magnesium treatment). Sea hares will consume it but are not a permanent solution.

Iridescent green spheres that appear harmless in small numbers but rapidly colonise rock if left unchecked. Emerald crabs are the most effective biological control. Do not pop bubbles — they release spores and worsen the outbreak. Manual removal requires extracting the entire holdfast; even fragments regrow.

Fine, fluffy dark green tufts that resemble a softer version of Bryopsis. Often appears in high-nutrient systems and around powerhead intakes. Like Bryopsis it is resistant to most herbivores. Sea hares will consume it; magnesium treatment (1500–1800 ppm) is effective. Reducing phosphate below 0.05 ppm also helps.

Flat, iridescent brown-olive blades that spread over rockwork and corals. Beautiful under certain lighting — shimmers blue-green — but highly invasive in reef tanks. Produces chemical deterrents that most fish avoid. Very difficult to eliminate; manual removal stimulates regrowth. Sea urchins (Diadema) and Thalassoma wrasses occasionally graze it.

Brown, stringy, bubble-filled slime that often appears in new reef tanks — frequently mistaken for cyanobacteria. Dinoflagellates ('dinos') form slimy mats that can smother corals and sandbed. Treatment is complex: raise nitrates (>2 ppm), raise phosphates (>0.05 ppm), run extended dark periods, and increase UV sterilisation. One of the most frustrating reef nuisances.

Majestic large angelfish with electric blue-and-yellow horizontal stripes. Juveniles are black with white rings. Not reef-safe. Requires expert care and very large tanks.

Beautiful coral with long flowing polyps resembling a field of flowers. Historically difficult to keep long-term. Requires stable, high-quality water and moderate flow.

Montipora is a diverse SPS coral genus second only to Acropora in species diversity, available in plating, branching, and encrusting growth forms in a wide array of colours. It is considered the entry-level SPS coral, more forgiving than Acropora but still demanding stable water parameters, high light, and good flow. Plating Montipora varieties are particularly popular for adding mid-level horizontal structure and bold colour to reef aquariums.

One of the most beautiful tangs with a powder-blue body, yellow dorsal fin and black mask. Prone to ich and disease — best for experienced reef keepers.

Spectacular non-photosynthetic coral with bright orange or yellow star-like polyps. Does not need light but requires target-fed mysis or brine shrimp every few days. Challenging but visually stunning — a showpiece coral.

A dense mat of mixed short filamentous algae — the dominant algae type on wave-swept reef flats in nature. In captivity it traps detritus and is extremely difficult to manually remove. Sea urchins (Diadema, Tuxedo) and tangs are the most effective grazers. Consider a manual scraping plus herbivore-stocking approach.